package com.yupi.springbootinit.utils;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.StrUtil;
import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.support.ExcelTypeEnum;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ObjectUtils;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * Excel相关工具类
 */
@Slf4j
public class ExcelUtils {

    /**
     * excel转csv
     * @param multipartFile
     * @return
     */
    public static  String excelToCsv(MultipartFile multipartFile) {
 /*       File file = null;
        try {
            file = ResourceUtils.getFile("classpath:test_excel.xlsx");
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e);
        }*/
        //先读取数据
        List<Map<Integer, String>> list = null;
        try {
            list = EasyExcel.read(multipartFile.getInputStream())
                    .excelType(ExcelTypeEnum.XLSX)
                    .sheet()
                    .headRowNumber(0)
                    .doReadSync();
        } catch (IOException e) {
            log.error("csv转化错误");
            //throw new RuntimeException(e);
        }
        if(CollUtil.isEmpty(list)){
            return null;
        }
        //转换成csv
        StringBuilder stringBuilder = new StringBuilder();
        //读取表头
        LinkedHashMap<Integer, String> headerMap = (LinkedHashMap) list.get(0);
        List<String> headerList =  headerMap.values().stream().filter(ObjectUtils::isNotEmpty).collect(Collectors.toList());
        stringBuilder.append(StrUtil.join(",", headerList)).append("\n");
        //读取数据
        for(int i = 1;i<list.size();i++){
            LinkedHashMap<Integer, String> dataMap = (LinkedHashMap)list.get(i);
            List<String> dataList =  dataMap.values().stream().filter(ObjectUtils::isNotEmpty).collect(Collectors.toList());
            stringBuilder.append(StrUtil.join(",", dataList)).append("\n");
        }
        return stringBuilder.toString();
    }


    public static void main(String[] args) {
        excelToCsv(null);
    }

}
